Hi! Whatever code I run on hadoop, reduce starts a few seconds after map finishes. And worse, when I run 10 jobs parallely (using threads and sending one after another) all maps finish sequentially, then after 8-10 seconds reduces start. I use reducer also as combiner, my cluster has 6 machines, namenode and jobtracker run also as slaves. There were 44 maps and 6 reduces in the last example, I never tried a bigger job.
What can the problem be? I've read somewhere that this is not the normal behaviour. Replication factor is 3. Thank you in advance for any pointers. Rasit
